The present invention relates to a device for locking a cap nut for a coupling, and more particularly to a device for locking a cap nut for a coupling, which is applied to the cap nut screwed with a body so as to prevent the cap nut from being released, so eventually securely assembling the connecting pipes not to be separated from the coupling.
Generally, a coupling is used for connecting pipes made of synthetic resin or metal used for a water purifier or chemical delivery. Such a coupling is required to be easily connected to the pipes, maintain sufficient watertight and sealing characteristics, and be securely fixed.
A conventional coupling 1 is shown in FIG. 1, and now described below in brief. As shown in FIG. 1, the coupling 1 includes a body 5, which is, at one side, connected to a connecting pipe 2a made of synthetic resin and, at the other side, connected to a connecting pipe 2 made of metal, and a cap nut 4 screwed with the body 5 when the metallic connecting pipe 2 is inserted into the body 5 for pressing a collet 3 to prevent the connecting pipe 2 from being deviated from the body 5.
In such a conventional coupling 1 constructed as above, because the collet 3 tightens the surface of the connecting pipe 2 when the cap nut 4 is screwed to connect the metallic connecting pipe 2 in the body 5, the connecting pipe 2 is securely connected and fixed to the coupling 1 not to be separated.
However, when the coupling 1 is applied to a vibrated product, it is possible that the screwed cap nut 4 is released due to continuous vibration for a long time because the coupling 1 does not have any locking device to prevent release of the cap nut 4. If the cap nut 4 is released, the collet 3 cannot tighten the surface of the connecting pipe 2, which makes the connecting pipe 2 separated from the coupling 1. Therefore, there is still a need to develop a coupling with a function of keeping tight combination between the coupling and the connecting pipe regardless of vibration.
Therefore, the present invention is designed to solve the problem of the prior art, and an object of the present invention is to provide a device for locking a cap nut for a coupling, which is applied to the cap nut screwed with a body so as to prevent the cap nut from being unscrewed due to vibration, so ensuring the connecting pipe not to be separated from the coupling.
In order to obtain the above object, the present invention provides a device for locking a cap nut for a coupling, which includes a body connected to a connecting pipe made of a synthetic resin at one side and connected to a connecting pipe made of a metal at the other side, and a cap nut screwed with the body when the metallic connecting pipe is inserted into the body for pressing a collet to prevent the connecting pipe from being deviated from the body, comprises a hooking plate extended out of the body which is connected to the metallic connecting pipe, a plurality of regularly spaced hooking protrusions protruded from the hooking plate, and a plurality of hooking grooves formed at positions facing the hooking protrusions and engaged with the hooking protrusions to prevent the cap nut from being released when screwing the cap nut.